-threshold <Real, >=0>
Minimum word score such that the word is added to the BLAST lookup
table

-comp_based_stats <String>
Use composition-based statistics for blastp / tblastn:
D or d: default (equivalent to 2)
0 or F or f: no composition-based statistics
1: Composition-based statistics as in NAR 29:2994-3005, 2001
2 or T or t : Composition-based score adjustment as in
Bioinformatics 21:902-911, 2005, conditioned on sequence
properties
3: Composition-based score adjustment as in Bioinformatics
21:902-911, 2005, unconditionally
For programs other than tblastn, must either be absent or be D, F
or 0
Default = `2'

-num_descriptions <Integer, >=0>
Number of database sequences to show one-line descriptions for
Default = `500'

-num_alignments <Integer, >=0>
Number of database sequences to show alignments for
Default = `250'